Abstract : The patent describes a starting circuit for a direct current motor which employs a zener diode to sense the back e.m.f. The zener diode is connected to a switch which effectively disconnects a current limiting impedance out of the armature circuit when the motor has obtained operating speed. In one arrangement, two zener diodes are used in combination to provide an adjustable control for the switching point. Another disclosed arrangement includes a current amplifier connected between the zener diode and the switch to provide for operation of the switch having a relatively high operating power requirement.